let crr= ['apple', 'strawberry', 'banana', 'pear', 'apple', 'orange', 'orange', 'strawberry']

function jiandanquchong(arr){
  let newArr=[]
  for(let i of arr){
    if(newArr.indexOf(i)===-1){
      newArr.push(i)
    }
  }
  return newArr
}

console.log(jiandanquchong(crr));